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Tips for using drill bits during construction
The drill bit is the main component of the rig. It is a tool that transmits impact energy, directly contacts the rock, and blasts. The bit is very complicated during the whole operation process, so there are high requirements for the material and shape of the drill bit. When using the eccentric drill bit, it is necessary to grasp the technical essentials. The selected drilling parameters should be based on the principle of low speed, low feed pressure and high return air speed. The hardness and looseness of the rock in the formation should be determined during the construction operation. Factors such as water content control the drilling speed. When the drill encounters a particularly loose or large fractured formation, it is especially necessary to reduce the feed rate and feed pressure, and repeatedly perform slag cleaning. In the specific construction operations, we should also pay attention to the following aspects:
1. Before the lower hole of the drilling tool, check whether the connection of the downhole impactor, the pipe drilling tool, the casing and the casing shoe is firm, whether the eccentric bit rotation is flexible and whether the ventilation is smooth.
2. During the drilling process, attention should be paid to the follow-up condition of the casing and the powder discharge in the hole. For every 0.3 to 0.4 m of drilling, the blown hole should be strongly blown to keep the hole clean. When blowing holes, the lifting distance of the center drilling tool should be strictly controlled to achieve strong blown hole discharge, and it is forbidden to vigorously lift the center drilling tool during the drilling process.
3. When the drilling is over or the central drilling tool needs to be replaced, the hole should be cleaned first, the bottom residue should be blown out, then the rotation will stop, and the center drilling tool will be lifted slowly. The lifting force can just lift the center. The drill is suitable to raise the height so that the back of the eccentric drill bit contacts the front end of the casing shoe; then the drill is reversed at a low speed, and the center drill is slowly lifted up. When it is observed that the center drilling tool can be smoothly upgraded, it indicates that the eccentric drill bit has been folded, and the center drilling tool can be lifted in a conventional manner until all the center drilling tools are proposed. Care should be taken when reversing the drill to prevent the drill from tripping.
4. Sometimes there is too much residual slag at the bottom of the hole, and the eccentric bit is swung by the slag and the eccentric bit is caught. When it is still not effective after several trials, the compressor should be transported, the drill hole should be cleaned again, and the down-the-hole hammer should be worked for a short time, and then the center drill lifting operation should be resumed.
DTH hammer and pipe drilling technology is an effective method to overcome the difficulty of drilling complex tunnels in engineering construction. Eccentric heel drills provide drilling for complex formations due to their unique structure and excellent working performance. A reliable technical guarantee. The specification series for heel drills used in engineering construction has also been increasingly perfected and developed from small bore radial large apertures.